Objective To evaluate if female gender is associated with renal insufficiency in patients with ST-elevation myocardial infarction (STEMI) and if there is a gender difference in the prognostic importance of renal insufficiency in STEMI.

Design Single-centre observational study.

Setting One tertiary cardiac centre.

Patients All consecutive patients with STEMI planned for primary percutaneous coronary intervention in one Swedish county in 2005 (98 women and 176 men).

Main outcome measures Logistic regression analyses were conducted to evaluate the predictors of renal insufficiency, associations between estimated glomerular filtration rate (eGFR) and outcome in each gender and a possible interaction between gender and eGFR regarding outcome.

Results Renal insufficiency was defined as eGFR less than 60 ml/min per 1.73 m². 67% of women had renal insufficiency compared with 26% of men, OR 5.06 (95% CI 2.66 to 9.59) after multivariable adjustment. In women each 10 ml/min per 1.73 m² increment of eGFR was associated with a 63% risk reduction for 1-year mortality, OR 0.37 (95% CI 0.15 to 0.89). No such association was found in men, OR 1.05 (95% CI 0.63 to 1.76). A trend towards a significant interaction between gender and eGFR regarding 1-year mortality was found, OR 2.05 (95% CI 0.93 to 4.50).

Conclusions A considerable gender difference in the prevalence of renal insufficiency in STEMI was found and renal insufficiency seemed to be a more important prognostic marker in women. These results are important as previous STEMI studies have shown higher multivariable adjusted mortality in women than in men but renal function has seldom been taken into consideration.